Low-Power Organic Light Sensor Array Based on Active-Matrix Common-Gate Transimpedance Amplifier on Foil for Imaging Applications Samar Elsaegh , Clemens V eit, Ute Zschieschang , Mohammad Amayreh , Florian Letzkus, Holger Sailer, Michael Jurisch, Joachim N. Burghartz , Uli Würfel, Hagen Klauk

Abstract

This article presents a 57.6- µW mechanically flex- ible active-matrix imaging system based on a 4 × 5 array of light sensors, each composed of a photodetector (PD) using a light-sensitive organic polymer and a transimpedance ampli- fier (TIA) based on organic thin-film transistors and integrated thin-film carbon resistors. The PDs and the electronics are fabricated on separate plastic films and integrated into a system. Two different topologies for the TIA are designed, implemented, and characterized. The first topology is a self-biased TIA based on a gain-boosted operational amplifier (op-amp), providing an open-loop dc gain of 41.3 dB. This op-amp-based TIA, with a feedback resistor, provides stable current-to-voltage conversion (0–100 µA and 2.0–3.7 V) at frequencies up to 300 Hz. The second topology is a low-power gain-boosted common-gate (GB CG) TIA that performs curren t-to-voltage conversion with a nonlinearity as small as ±0.3% within a bandwidth of 1 kHz. The output voltages of the light sensors are read and converted into a 4 × 5 pixel gray-scale image displayed on a computer monitor to visualize the functionality of the system.